How Does The Permeate Pump Reduce Waste Water By 80%?
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Background
Several factors have an effect on the production capability and efficiency of a Reverse Osmosis system. Among them are the incoming water PSI, temperature of the incoming water, size of the RO membrane, amount of contaminants in the incoming water and the amount of water being sent to the drain. All of the components of an RO system are important to the over – all operation of the unit, however the Permeate Pump stands out as the component that provides finishing touches to production efficiency.
How Does The Permeate Pump Reduce Waste and Increase Efficiency?
The product water production rate is dependent on the pressure across the membrane, while the waste water production rate is mostly dependent on tap water pressure. As a bladder tank fills with water, its back pressure quickly starts to reduce the working pressure across the membrane, while the waste water flows as always. A curve can be plotted that shows progressively worsening ratios as the tank continues to fill. Half-way through the filling time, the ratio is already 8 or 10 to 1 and can be higher than 20:1 at the moment the ASO valve shuts off completely. The permeate pump makes the membrane perform like the bladder isn’t there. The pump removes the pressure from the back side of the membrane and allows the system to function as if it were not forcing water into a tank. All of the work goes into making water. So, yes the pump can save up to (80%) of the normal waste water. The permeate pump works to eliminate this line pressure and allows the water to flow freely through the membrane and into the tank. An added benefit to the permeate pump is it drastically reduces the amount of waste water an RO produces. These pumps are used for pressure ranges from 30-75psi.
Production Results
A RO unit with a permeate pump and 60 psi coming in will continue to produce water until pressure in the tank reaches almost 60 psi. This is especially helpful for low-pressure installations. If, for example, you have a well system that provides only 40 psi, a standard RO unit will run, but it won’t run well. The unit will shut down when tank pressure reaches 25 psi or so. With a permeate pump, the unit will put almost the full 40 psi into the storage tank.
What’s best about the permeate pump, though, is the increased efficiency. With a standard shutoff system, as the storage tank fills, the RO unit must push against an increasing amount of storage tank pressure. With the permeate pump, the unit is shielded from this pressure and the membrane works in a virtually pressure-free situation, even when the tank is almost full.
